Catheter having improved bonding region

ABSTRACT

A catheter having a flexible outer tube and a lubricious inner tube bonded within the flexible outer tube. One catheter has a distal outer tube formed of a substantial portion of a first, flexible material, an inner tube having a lubricious inside wall surface formed of a second, lubricious material, and an outer tube wall surface compatible with heat bonding the inner tube outside wall surface to the outer tube wall surface. A preferred flexible material is polyether block amide (PEBA) and a preferred lubricious material is polyethylene. One catheter utilizing the invention includes a flexible distal outer tube having an orifice through the tube wall and an inner tube inserted through the orifice having a lubricious inner layer surrounded by a tie-layer, surrounded in turn by the same flexible material forming the outer tube. One catheter has a PEBA outer tube heat bonded to a tri-layer inner guide wire tube formed of a polyethylene inner layer, a PEBA outer layer, and a PLEXAR™ tie-layer disposed between the inner and outer layers.

FIELD OF THE INVENTION

[0001] The present invention relates generally to medical devices. Morespecifically, the present invention relates to angioplasty catheters. Inparticular, the present invention includes angioplasty catheters havingdistal, short, lubricious inner guide wire tubes bonded within flexibleouter tubes.

BACKGROUND OF THE INVENTION

[0002] Angioplasty procedures have gained wide acceptance in recentyears as efficient and effective methods for treating types of vasculardisease. In particular, angioplasty is widely used for opening stenosesin the coronary arteries and is used for treating stenoses in othervascular regions.

[0003] One widely used form of angioplasty makes use of a dilatationcatheter which has a inflatable balloon at the distal end and a guidewire lumen within at least a portion of the catheter shaft. Typically, aguide wire is inserted through the vascular system to a position nearthe stenoses, leaving a proximal portion of the guide wire extendingfrom the patient. The proximal guide wire portion is threaded throughthe dilatation catheter guide wire lumen, and the dilatation catheter isadvanced through the vascular system over the guide wire to a positionnear the stenoses. The treating physician manipulates the dilatationcatheter until the balloon is positioned across the stenoses. Theballoon is then inflated by supplying fluid under pressure through aninflation lumen in the catheter to the balloon. The inflation of theballoon widens the vessel lumen through the stenosed area by pressingthe inflating balloon wall against the lesion inside wall.

[0004] One class of dilatation catheters, termed “Single OperatorExchange” (SOE) or “Rapid Exchange” catheters, have only a short, distalguide wire lumen, to allow for easy removal and replacement of catheterswhile requiring only a short length of guide wire extending proximallyfrom a patient. These catheters include a distal portion having multipledesired attributes. The catheter distal portion preferably has a smallprofile or cross-sectional area and is very flexible, to allow fortraversing narrow and tortuous vessel paths. The distal portion may alsorequire a guide wire tube having a lumen, which increases the profile.The guide wire lumen preferably has a lubricious inside wall to easemovement of the catheter over the guide wire.

[0005] Many current SOE catheters have outer polyethylene tubes andinner polyethylene guide wire tubes inserted therein. An orifice can becreated in the side of the outer tube wall and the inner tube insertedthrough the orifice. The inner tube is inserted so as to extendlongitudinally through the lumen of the outer tube. On one side of theinner tube, distal of the orifice, the outside surface of the inner tuberuns close to the inside surface of the outer tube. On the oppositedirection, proximal of the orifice, the outside surface of the innertube runs along the outside surface of the outer tube, in a crimped orbuckled hollow surface region. The close proximity of the tube surfacessuggests bonding using adhesive or heat bonding. Heat bonding ispreferred to adhesive bonding.

[0006] Polyether block amide (PEBA) tubes have greater flexibility thanpolyethylene tubes, and it would be desirable to use PEBA tubes for theouter tubes. It is very desirable to have the inner and outer tubesformed of mutually compatible materials to enable heat bonding. Use ofPEBA for guide wire inner tubes would provide such heat bondingcompatibility. PEBA is generally less lubricious than polyethylene,however, making polyethylene a more desirable material for forming theinner tube. Lubricity is important for providing a low friction innersurface for accepting a guide wire. What would be desirable is acatheter allowing for use of a more flexible outer tube while retainingthe benefits of a more lubricious inner tube while allowing high-qualityheat bonding between the two tubes.

SUMMARY OF THE INVENTION

[0007] The present invention includes catheters having a first tubeformed primarily of a first material bonded to a second tube having aninside surface formed primarily of a second material, where the firstand second materials may be unsuited for high quality direct bonding.One catheter has a first tube formed of a flexible material such aspolyether block amide and a second, tri-layer tube having a lubriciousinside layer such as polyethylene, a flexible outside layer formed ofthe same material as the first tube outside surface, and an intermediatetie-layer suitable for joining the lubricious and flexible layers. In apreferred embodiment, the first tube has an orifice through a wall andthe second tube is inserted through the wall and distally disposedwithin the first, outer tube. In a preferred embodiment, the first tubefunctions as a distal catheter shaft and the second tube functions as ashort, distal guide wire tube disposed within, and bonded to, the firsttube.

[0008] Catheters incorporating the invention include single operatorexchange (SOE) angioplasty balloon catheters having a proximal shaft, adistal shaft including a first tube coupled to the proximal shaft,distally disposed inflatable balloon, and an orifice through the wall ofthe first tube disposed proximal of the balloon. In these catheters, asecond guide wire tube can be inserted through the orifice and disposeddistally of the orifice, commonly extending through the balloon regionand ending in a distal guide wire port near the distal end of thecatheter. The SOE catheters preferably have a lubricious materialforming the inside layer of the inner tube and a flexible materialforming most of the outer tube. A preferred lubricious material ispolyethylene (PE) and a preferred flexible material is polyether blockamide (PEBA).

[0009] One SOE catheter has a polyethylene inner tube disposed within atri-layer outer tube having an inside PE layer, an outer PEBA layer, anda PLEXAR™ tie-layer disposed therebetween. The outer tube inside surfacecan be bonded to the inner tube outside surface. Another SOE catheterhas a PE inner tube disposed within an interrupted tri-layer outer tubehaving a proximal PE portion, a distal PEBA portion, and a tie-layerinterrupting the PE and PEBA portions. The inner tube outside surfacecan be bonded to the outer tube PE portion inside and outside surfaces.Another SOE catheter has a PEBA outer tube and an interrupted tri-layerinner tube disposed therein having a proximal PEBA portion, a distal PEportion, and a tie-layer disposed therebetween. The inner tube PEBAportion can be bonded to the outer tube PEBA inside and outsidesurfaces. Another SOE catheter includes a PEBA outer tube and a PE innertube having a proximal tri-layer portion having a tie-layer disposedover the inside PE layer and a PEBA layer disposed over the tie-layer.The inner tube proximal portion outside PEBA surface can be bonded tothe outer tube PEBA inside and outside surfaces.

[0010] Yet another SOE catheter includes a PEBA outer tube and atri-layer inner tube having a PE inside layer, a PEBA outside layer, anda tie-layer disposed therebetween. The inner tube outside PEBA surfacecan be bonded to the outer tube PEBA inside and outside surfaces. Instill another SOE catheter, an outer PEBA tube has a bi-layer inner tubedisposed within including an inside high density PE (HDPE) layer and aPLEXAR™ tie-layer disposed over the HDPE inside layer. The inner tubeoutside tie-layer can be bonded to the outer tube PEBA inside surface.In one more embodiment, an SOE catheter includes a PEBA outer tube andan inner tube having a proximal PEBA portion butt-welded to a distaltri-layer portion having a PE inside layer, a PEBA outside layer, and atie-layer disposed therebetween.

[0011] The present invention can provide catheters having the advantagesof a lubricious guide wire tube, a flexible catheter shaft, and a securebond between the lubricious material and the flexible material.Catheters according to the present invention can provide the advantagesof both materials as well as providing the advantages of heat bondingthe two materials.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a longitudinal, cross-sectional view of a balloonangioplasty catheter including an inner guide wire tube inserted throughan orifice in an outer tube and disposed within the outer tube;

[0013]FIG. 2 is a fragmentary, longitudinal cross-sectional view of adistal portion of the catheter of FIG. 1, illustrating an inner tubeextending through an orifice in an outer tube;

[0014]FIG. 3 is a transverse, cross-sectional view taken through 3-3 inFIG. 1, illustrating an outer tube, an inner tube, and a core wire;

[0015]FIG. 4 is a longitudinal, cross-sectional view of an inner guidewire tube inserted within and bonded to a tri-layer outer tube, whereinthe outer tube has an inside surface compatible with the outside surfaceof the inner tube;

[0016]FIG. 5 is a longitudinal, cross-sectional view of a tri-layerinner guide wire tube inserted within and bonded to an outer tube,wherein the inner tube has an outside surface compatible with the insidesurface of the outer tube;

[0017]FIG. 6 is a longitudinal, cross-sectional view of an inner guidewire tube inserted within and bonded to an interrupted tri-layer outertube, wherein the outer tube has a proximal portion inside surfacecompatible with the outside surface of the inner tube, an intermediateportion tie-layer, and a distal portion having different properties thanthe proximal portion;

[0018]FIG. 7 is a longitudinal, cross-sectional view of an interruptedtri-layer inner guide wire tube inserted within and bonded to an outertube, wherein the inner tube has a proximal portion outside surfacecompatible with the inside surface of the outer tube, an intermediateportion tie-layer, and a distal portion having different properties thanthe proximal portion;

[0019]FIG. 8 is a longitudinal, cross-sectional view of an inner guidewire tube inserted within and bonded to an outer tube, wherein the innertube has a short, proximal tri-layer portion having an outside surfacecompatible with the inside surface of the outer tube and a distalportion having an outside surface corresponding to the inside layer ofthe tri-layer portion;

[0020]FIG. 9 a longitudinal, cross-sectional view of a bi-layer innerguide wire tube inserted within and bonded to an outer tube, wherein theinner tube has an outside tie-layer compatible with the inside surfaceof the outer tube; and

[0021]FIG. 10 is a longitudinal, cross-sectional view of an inner guidewire tube inserted within and bonded to an outer tube, wherein the innertube has a proximal portion having an outside surface compatible withthe inside surface of the outer tube and a distal portion havingdifferent properties than the proximal portion butt-welded to theproximal portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022]FIG. 1 illustrates a balloon angioplasty catheter 20, whichdemonstrates one catheter incorporating the present invention. Catheter20 extends from a proximal region 22 through an intermediate region 24to a distal region 26. Proximal region 22 includes a manifold 28, astrain relief 30, and a proximal shaft 32. Proximal shaft 32 includes aproximal region 34 having an outer hypotube construction and a distalregion 36 having a polymeric construction, continuing distally after thehypotube terminates. The term “hypotube,” as used herein, refersgenerally to a thin walled, high-strength metallic tube having a lumenwithin. The hypotube is preferably a stainless steel hypodermic tube. Inone embodiment, a core wire or stiffener 37 can be included in proximalregion 22 and intermediate region 24 to provide additional stiffness andpushability to catheter 20 to enable pushing the catheter distal portioninto distant body regions without buckling.

[0023] A distal shaft 42 includes an outer tube 46 and an orifice 48through the outer wall of outer tube 46 and a lumen 47 within. A balloon50 is disposed distally on distal shaft 42, having an envelope 52, aproximal waist 54, and a distal waist 56. An inner tube 58 is insertedinto outer tube 46 and lumen 47 through orifice 48. Inner tube 58 servesas a distal guide wire tube in catheter 20. The relatively short lengthof inner tube 58 allows the single operator or rapid exchange ofcatheter 20 over a guide wire. Inner tube 58 includes a proximal orifice70, a proximal end 71, a proximal portion 60, an intermediate portion62, a distal portion 64, a distal end 66, a distal orifice 68, and aguide wire lumen 59 within. In use, a guide wire (not requiringillustration) can be threaded through proximal orifice 70, through lumen59, exiting through distal orifice 68. Inner tube 58 is preferablysubstantially congruent within outer tube 46 for much of the length ofinner tube 58. The entry of inner tube 58 through orifice 48 can includea buckled or concave region 72, also illustrated in FIG. 2 at 806. Inthis buckled region, inner tube 58 can lie atop outer tube 46 proximalof entry orifice 48. The entry of inner tube 58 into outer tube 46preferably includes bonding or affixing of the tubes to secure innertube 58 in place. This bonding preferably includes bonding in the regionproximate orifice 48 and can include bonding both proximal and distal oforifice 48.

[0024] Referring now to FIG. 2, the region proximate the entry of theinner tube into the outer tube is illustrated in greater detail. Theembodiments illustrated in FIGS. 4-10 can share many of the structuralfeatures of the embodiment of FIG. 2, while having different tubeconstruction and bonding. FIG. 2 illustrates a catheter distal region800 including an outer tube 802 having an orifice 804 therein and aninner guide wire tube 805 inserted distally though orifice 804. Anorifice such as orifice 804 can be formed by making a slit or removingmaterial and creating a hole in the outer tube wall. The orifice canserve to admit the inner tube into the outer tube. Inner tube 805includes a proximal end 810, a proximal portion 812, a proximal orifice808, and a guide wire lumen 816 through inner tube 805. Inner tube 805lies in a buckled or concave region 806 in outer tube 802 proximal ofwhere inner tube proximal portion 812 extends into outer tube 802. Inone embodiment, the bonding region lies generally proximate orifice 804,which can be used for bonding of inner tube 805 to outer tube 802. Innertube 805 includes an inner tube wall 818, an inside wall surface 822,and an outside wall surface 820. Inner tube 805 includes a distalportion 814, which lies distal of proximal portion 812. Outer tube 802includes a proximal portion 830, a tube wall 831, an outside wallsurface 832, and an inside surface 840.

[0025] In one embodiment, inner tube wall 818 is formed of a lubriciousmaterial to provide a lubricious inside surface 822 offering lessresistance when advancing the catheter over a guide wire. In thisembodiment, outer tube wall 831 is formed of the same or compatiblelubricious material as inner tube 805. This allows bonding between innerand outer tubes as indicated, for example, at region 850. In someembodiments, bonding occurs distal of orifice 804 and near orifice 804.In other embodiments, the bonding occurs further distal of orifice 804.In other embodiments, bonding occurs proximal of orifice 804 asindicated, for example, by region 851. Any suitable location for bondinginner to outer tubes is within the scope of the invention.

[0026] Referring now to FIG. 3, a transverse cross section taken through3-3 in FIG. 1 is further illustrated. Outer tube 46 has been heat bondedto inner tube 58, resulting in an area of melted polymer 47 between theinner and outer tubes. Guide wire lumen 59 is illustrated, together withcore wire 37 and an inflation lumen 61. In one method, after the innertube is positioned within the outer tube, mandrels corresponding to theguide wire and inflation lumens are positioned within the inner andouter tubes respectively. The tubular assembly is heated, resulting in are-melt or re-flow of polymeric material and heat bonding.

[0027] Referring now to FIG. 4, a catheter distal region 100 isillustrated, including an outer tube 102 having an orifice 104 therein,and an inner guide wire tube 105 inserted distally though orifice 104.Inner tube 105 includes a proximal portion 112 and a guide wire lumen116 through inner tube 105. Inner tube 105 lies in a buckled or concaveregion 106 in outer tube 102 proximal of where inner tube proximalportion 112 extends into outer tube 102. In one embodiment, the bondingregion lies generally proximate orifice 104, which can be used forbonding of inner tube 105 to outer tube 102. Inner tube 105 includes aninner tube wall 118, an inside wall surface 120, and an outside wallsurface 122. Inner tube 105 includes a distal portion 114, which liesdistal of proximal portion 112. Outer tube 102 includes a proximalportion 130, a tube wall 131, an outside wall surface 132, an outsidelayer 134, an intermediate tie-layer 136, an inside layer 138, and aninside surface 140.

[0028] In one embodiment, inner tube wall 118 is formed of a lubriciousmaterial to provide a lubricious inside surface 120 offering lessresistance when advancing the catheter over a guide wire. In thisembodiment, outer tube wall inside surface 140 is formed of the same orcompatible lubricious material as inner tube 105. This allows bondingbetween inner and outer tubes as indicated in region 150. As illustratedin FIG. 4, inner tube 105 and outer tube inner layer 138 are formed ofthe same material. After heat bonding, the two layers can melt and flowtogether as indicated by the dashed line between layer 138 and innertube wall 105. In the example illustrated, bonding only occurs distal oforifice 104 and near orifice 104. In other embodiments, the bondingoccurs further distal of orifice 104. Any suitable location for bondinginner to outer tubes is within the scope of the invention. Outer tube102 has an outside layer 134 formed of a flexible material differentfrom the lubricious material forming inner tube 105. Disposed betweenoutside layer 134 and inside layer 138 is tie-layer 136.

[0029] Tie-layer 136, as used herein, refers to a layer which enables orenhances the bonding of the two materials such as the outside and insidelayers to one another. The outer tube outside and inside layers canprovide different properties desirable for the catheter. In particular,the outside layer can contribute much of the structural properties ofthe outer tube, while the inside layer can contribute an inside surfacethat is bond compatible with the outside surface of the inner tube. Thetie-layer is preferably a layer of polymer that is bond compatible withboth inside and outside layers. The tie-layer can in turn be formed ofmore than one layer, but a single layer is preferred to provide a thintube wall. In some embodiments, the tie-layer enables two materials tobond to one another where such bonding would not occur in the absence ofthe tie-layer. In other embodiments, the tie-layer enhances bonding,improving the bond strength over that which would otherwise occur. Atie-layer can greatly improve the quality of bonding.

[0030] In one embodiment, inner tube 105 is formed of polyethylene,outer tube inside layer 138 is also formed of polyethylene, and outertube outside layer 134 is formed of a polyether block amide (PEBA) suchas PEBAX™. A tie-layer suited for bonding polyethylene and PEBA togethersuch as PLEXAR™ or KRATON™ is used for tie-layer 136 in one embodiment.In some embodiments, a surface treatment can be used to form thetie-layer. In an embodiment having a polyethylene inner tube, thepolyethylene provides a lubricious inside tube surface for a guide wireto slide within. In an embodiment having a PEBA outer tube outer layer,the PEBA provides a strong, yet flexible material, having superiorflexibility to polyethylene in most catheter applications. Theflexibility is of importance in the distal catheter region, which may berequired to traverse tortuous secondary and tertiary coronary vessels.

[0031] The polyethylene inner tube provides the advantages of alubricious inner surface, while the tri-layer outer tube providesflexibility imparted by the PEBA outside layer. The polyethylene outertube inside layer provides a layer compatible for heat bonding with thepolyethylene inner tube outside surface. The outer tube tie-layerprovides a means for joining the outer tube polyethylene and PEBAlayers. Catheter distal region 100 thus has the advantages of alubricious guide wire lumen and the advantages of a distal catheterouter tube formed of a flexible material.

[0032] Referring now to FIG. 5, another embodiment of the invention isillustrated in a catheter distal region 200 including an inner tube 205disposed within an orifice 204 in an outer tube 202. Outer tube 202includes a proximal portion 230, a tube wall 231, an outside surface232, and an inside surface 240. Outer tube 202 and tube wall 231 areformed of a first material extending from outside surface 232 to insidesurface 240. Inner tube 205 includes a tube wall 218 having an insidesurface 220, an inside layer 221, a tie-layer 225, an outside layer 223,and an outside surface 222. Inner tube inside layer 221 is formed of asecond, lubricious material, and outside layer 223 is preferably formedof the first material or a material bond compatible with the firstmaterial. Tie-layer 225 provides a bond, holding inside layer 221 andoutside layer 223 together. Outer tube inside surface 240 and inner tubeoutside surface 222 are formed of the same first material, allowing forformation of a good heat bond securing the inner tube within the outertube. In the bonding region proximate orifice 204, the inner and outertubes are secured at a distal bonding region 250 disposed distal oforifice 204 and at a proximal bonding region disposed proximal oforifice 204, better visualized by bonding region 851 in FIG. 2, as areother bonding regions disposed proximal of the orifice in FIGS. similarto FIG. 5. Outer tube 202 can be bonded to inner tube 205 using bothouter tube inside surface 240 and outside surface 222. In a preferredembodiment, the first material forming outer tube 202 is PEBA, as is thematerial forming inner tube outside layer 223, while the second materialforming inner tube inside layer 221 is polyethylene. The embodimentillustrated thus can have a lubricious polyethylene inside surface forthe guide wire lumen and a flexible PEBA outer tube.

[0033] Referring now to FIG. 6, a catheter distal region 300 having aninterrupted tri-layer outer tube is illustrated. Catheter distal region300 includes an inner tube 305 disposed within an orifice 304 in anouter tube 302. Inner tube 305 includes a wall 318, an inside surface320, and an outside surface 322. Outer tube 302 includes a tube wall 331having an inside surface 340, an outside surface 332, a proximal portion330, a distal portion 342, and an intermediate portion 337 disposedbetween the proximal and distal portions. In a preferred embodiment,intermediate portion 337 includes a tie-layer 336 formed as a shortlayer disposed at an angle relative to the tube wall, such thattie-layer 336 extends over a length indicated at “D1” in FIG. 6.Tie-layer 336, as illustrated, longitudinally separates or interruptsthe proximal and distal portions of the layer. In a preferredembodiment, D1 has a length between about one (1) mm and one hundred(100) mm and a width of about one hundred (100) mm. In one method,tie-layer 336 is formed using a Short and Controlled Transition Section(SCTS) extrusion technique, as described in U.S. Pat. No. 5,533,985,issued to Wang, herein incorporated by reference. In one embodiment,inner tube 305 is formed of polyethylene, and outer tube 302 hasproximal portion 330 formed of polyethylene, tie-layer 336 formed ofPLEXAR™, and distal portion 342 formed of PEBA. In one embodiment, innertube outside surface 322 is bonded to outer tube inside surface 340, asindicated at 350 and by region 851 in FIG. 2 as discussed previously. Inembodiments supporting bonding involving both the inside and outsidesurface of the outer tube, the bonding region can extend both proximaland distal of orifice 304. Bonding can also extend over the sides ofinner tube 305 but is not illustrated in the longitudinal,cross-sectional view of FIG. 6. The embodiment of FIG. 6 thus provides alubricious inner tube for ease of guide wire movement and an outer tubeproximal portion for bonding to the lubricious inner tube, whileproviding a flexible material forming most of the outer tube.

[0034] Referring now to FIG. 7, a catheter distal region 400 having aninterrupted tri-layer inner tube is illustrated. Catheter distal region400 includes an outer tube 402 having an inner tube 405 disposed withinan orifice 404 in outer tube 402. Inner tube 405 includes a proximalportion 412, a distal portion 414, and an intermediate portion 413having a length indicated at “D2”. Intermediate portion length D2 ispreferably between about one (1) mm and fifty (50) mm. Intermediateportion 413 includes a tie-layer 436 preferably disposed at an anglerelative to the inner tube wall. In one method, tie-layer 436 is formedusing a Short and Controlled Transition Section (SCTS) extrusiontechnique previously described. Outer tube 402 and inner tube proximalportion 412 are preferably formed of the same flexible material to allowfor improved bonding. Inner tube distal portion 414 is preferably formedof a lubricious material, while tie-layer 436 is preferably formed of amaterial suitable for adhering the flexible and lubricious materialstogether. In one embodiment, the inner tube proximal portion 412 isbonded to outer tube 402, as indicated at 450 and by region 851 in FIG.2. The embodiment illustrated thus provides a lubricious material formost of the length of inner tube 405, while providing a flexiblematerial for outer tube 402. Forming inner tube proximal portion 412 ofa bond compatible or identical material to the material of the outertube allows bonding together of the inner and outer tubes.

[0035] Referring now to FIG. 8, a catheter distal region 500 isillustrated having an inner tube 505 inserted into an orifice 504 in anouter tube 502. Inner tube 505 includes a tube wall 518, a proximalportion 512, and a distal portion 514. In proximal portion 512, innertube wall 518 includes an inner layer 517, which is preferably formed ofthe same material as the entire tube wall at distal portion 514, atie-layer 536 disposed over the tube wall or inner layer 517, and anoutside layer 534 disposed over the tie-layer. The proximal portion ofinner tube 505 thus can have two added outer layers in the proximalportion. In a preferred embodiment, outer tube 502 is formed of aflexible material and inner tube outside layer 534 is formed of the samematerial, thereby allowing for bond compatibility between inner andouter tubes. In a preferred embodiment, inner tube wall 518 is primarilyformed of a lubricious material, and tie-layer 536 is formed of amaterial able to bond to both the inner lubricious material and theouter flexible material. In the embodiment illustrated, bonding occursas indicated at 550 and at 851 in FIG. 2. In one embodiment, inner tubeproximal portion 512 is formed using SCTS technology previouslydescribed. The portion of inner tube having the tie-layer and outsidelayer can be disposed anywhere on the inner tube where bonding to theouter tube is contemplated. In one embodiment, multiple short tri-layerportions are disposed over the length of the inner tube. In thisembodiment, the added two layers are added to an inner tube whereneeded. The additional two layers over the inner tube preserves thelubricious inner walls of the inner tube while improving the bondingcompatibility between the inner and outer tubes. In one embodiment,inner tube inside layer 517 and distal portion 514 are formed ofpolyethylene, tie-layer 536 is formed of PLEXAR™, and outside layer 534is formed of PEBA. The embodiment provides a lubricious lumen wall forguide wire movement and a flexible catheter outer tube.

[0036] Referring now to FIG. 9, a catheter distal region 600 isillustrated having a two-layer inner tube 605 disposed within an orifice604 and in an outer tube 602. Inner tube 605 has a tube wall 618 formedof an inside layer 638 and an outside tie-layer 636. Inner tube insidelayer 638 is preferably formed of a lubricious material and outer tube602 is preferably formed of a flexible material different from thematerial forming the inner tube inside layer. Bonding between inner andouter tubes is indicated at 650, but the bonding location is varied indifferent embodiments. In one embodiment, inside layer 638 is formed ofpolyethylene, tie-layer 636 is formed of PLEXAR™, and outer tube 602 isformed of PEBA. The catheter distal region illustrated in FIG. 9 canhave a lubricious inner tube inside wall for guide wire movement and aflexible outer tube wall.

[0037] Referring now to FIG. 10, a catheter distal region 700 having abutt-welded proximal portion is illustrated. Catheter distal region 700includes an inner tube 705 inserted into an orifice 704 and disposedwithin an outer tube 702. Inner tube 705 includes a proximal portion 712butt-welded to a distal portion 714. A weld 713 is indicated between theproximal and distal portions. In one embodiment, outer tube 702 isformed of a flexible material and inner tube proximal portion 712 isformed of the same or a bond compatible material. Inner tube distalportion 714 can include a tri-layer tube wall as illustrated, having aninside layer 738, an outside layer 734, and a tie-layer 736 disposedbetween inside layer 738 and outside layer 734. In a preferredembodiment, outer tube 712 is formed from PEBA, as is inner tubeproximal portion 712. In this embodiment, inner tube distal portion 714includes inside layer 738 formed from polyethylene, where tie-layer 736can be formed from PLEXAR™ and outside layer 734 can be formed fromPEBA. The tri-layer inner tube can provide a lubricious inner surfacefor guide wire movement, while retaining the flexibility contribution ofthe PEBA outer layer. In this embodiment, bonding can occur as indicatedat 750 and 851 in FIG. 2. The embodiment illustrated thus has asubstantial PEBA contribution to flexibility, while providing alubricious guide wire lumen, as most of the inner tube inside layer canbe formed of polyethylene.

[0038] FIGS. 4-10 illustrate embodiments of the invention including anorifice through an outer tube wall and an inner tube inserted throughthe orifice into the outer tube and disposed distal thereof within theouter tube lumen. In another embodiment, a guide wire tube is disposedwithin an outer tube without being inserted through a wall. In thisembodiment, the outside surface of the inner tube is bonded to theinside surface of the outer tube. FIGS. 4-10, and the associated text,illustrate examples of tube construction and materials compatible withthis embodiment. In yet another embodiment, a first flexible tube has asecond tube having a lubricious inside surface bonded to the first tubeoutside surface. The second tube can serve as a guide wire tube. In avariation of this embodiment, multiple short, external tubes serve asguide wire tubes. FIGS. 5-10, and the associated text, illustrateexamples of tube construction and materials compatible with theseexternal guide wire tube embodiments. In these embodiments, the secondguide wire tube outside surface is bonded to the first tube outsidesurface.

[0039] In a preferred method of making the present invention, the firstand second tubes are heat bonded together in the bonding region. Otherbonding methods can also be used to take advantage of the compatiblematerials presented for bonding by the present invention. Other bondingmethods believed suitable for use with the present invention includesonic welding and solvent welding.

[0040] Numerous characteristics and advantages of the invention coveredby this document have been set forth in the foregoing description. Itwill be understood, however, that this disclosure is, in many respects,only illustrative. Changes may be made in details, particularly inmatters of shape, size and ordering of steps without exceeding the scopeof the invention. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. A catheter shaft comprising: a first tubeincluding a lumen, an inside wall surface, and an outside wall surface,said first tube having an orifice in a proximal portion of said firsttube; a second tube inserted through, and extending distally from, saidorifice, said second tube having a length, a lumen therethrough, aproximal portion, an inside wall surface and an outside wall surface;and a bonding region bonding said second tube outside wall surface tosaid first tube wall surface, said second tube inside wall surface beingformed of a second, lubricious material for a majority of said secondtube length, said first tube wall having a layer of a first, flexiblematerial extending for a majority of said first tube length, said firstmaterial being different from said second material.
 2. A catheter shaftas recited in claim 1, wherein said bonding region is proximate saidorifice.
 3. A catheter shaft as recited in claim 1, wherein said bondingregion includes bonding between said first tube outside surface and saidsecond tube outside surface proximal of said orifice and said bondingregion includes bonding between said first tube inside surface and saidsecond tube outside surface distal of said orifice.
 4. A catheter shaftas recited in claim 1, wherein said second tube inside and outside wallsurfaces are formed of said second material.
 5. A catheter shaft asrecited in claim 4, wherein said second tube wall is formed ofsubstantially said second material therethrough.
 6. A catheter shaft asrecited in claim 5, wherein said first tube inside surface is formed ofsaid second material proximate said bonding region.
 7. A catheter shaftas recited in claim 6, wherein said first tube has said second materialdisposed over most of said first tube inside surface proximate saidbonding region and distal of said bonding region.
 8. A catheter shaft asrecited in claim 7, wherein said first tube includes said secondmaterial as an inside layer, said first material as an outside layer,and a tie-layer disposed between said inside and outside layers.
 9. Acatheter shaft as recited in claim 6, wherein said second tube includespolyethylene, said first tube includes an inside layer of polyethylene,an outside layer of PEBA, and a tie-layer disposed between said insideand outside layers.
 10. A catheter shaft as recited in claim 6, whereinsaid first tube has said inside surface formed of said second materialproximate said bonding region and has said inside surface formed of saidfirst material distal of said bonding region.
 11. A catheter shaft asrecited in claim 10, further comprising a transition tie-layer disposedbetween said first and second materials.
 12. A catheter shaft as recitedin claim 11, wherein said second tube includes polyethylene and saidfirst tube includes polyethylene proximate said bonding region and saidfirst tube is formed of PEBA distal of said tie-layer.
 13. A cathetershaft as recited in claim 1, wherein said first tube inside surfaceincludes said first material.
 14. A catheter shaft as recited in claim13, wherein said first tube inside and outside surfaces are formed ofsaid first material.
 15. A catheter shaft as recited in claim 14,wherein said first tube is formed of said first material proximate saidbonding region and distal of said bonding region.
 16. A catheter shaftas recited in claim 15, wherein said second tube has a proximal portionproximate said bonding region having an outside surface formed of saidfirst material.
 17. A catheter shaft as recited in claim 15, whereinsaid second tube is formed of said first material in said proximalportion and formed of said second material distal of said proximalportion and has a transition tie-layer therebetween.
 18. A cathetershaft as recited in claim 17, wherein said first material includes PEBAand said second material includes polyethylene.
 19. A catheter shaft asrecited in claim 15, wherein said second tube is formed of said secondmaterial, said second tube proximal portion includes a tie-layerdisposed over said second material and an outer layer of said firstmaterial disposed over said tie-layer.
 20. A catheter shaft as recitedin claim 19, wherein said first material includes PEBA and said secondmaterial includes polyethylene.
 21. A catheter shaft as recited in claim15, wherein said second tube has said inside layer formed of said secondmaterial, a tie-layer disposed over said inside layer, and an outsidelayer formed of said first material disposed over said tie-layer.
 22. Acatheter shaft as recited in claim 21, wherein said first materialincludes PEBA and said second material includes polyethylene.
 23. Acatheter shaft as recited in claim 15, wherein said second tube proximalportion is formed of said first material and said second tube distal ofsaid proximal portion is bonded to said proximal portion and has aninside layer formed of said second material, a tie-layer disposed oversaid inside layer, and an outer layer formed of said second materialdisposed over said tie-layer.
 24. A catheter shaft as recited in claim23, wherein said first material includes PEBA and said second materialincludes polyethylene
 25. A catheter shaft as recited in claim 15,wherein said second tube proximal and distal portions have an insidelayer formed of said second material and an outside tie-layer disposedover said inside layer.
 26. A catheter shaft as recited in claim 25,wherein said first material includes PEBA and said second materialincludes polyethylene, wherein said second tube outside tie-layer wallsurface is heat bonded to said first tube inside wall PEBA surfaceproximate said orifice.
 27. A catheter shaft comprising: a first tubeincluding a lumen, an inside wall surface, and an outside wall surface;a second tube disposed at least partially within said first tube, saidsecond tube having a length, a lumen therethrough, an inside wallsurface and an outside wall surface; and a bonding region bonding saidsecond tube outside wall surface to said first tube wall surface, saidsecond tube inside wall surface being formed of a second material for amajority of said second tube length, said first tube wall having a layerof a first material extending for a majority of said first tube length,said first material being different from said second.
 28. A cathetershaft as recited in claim 27, wherein said first material and saidsecond material form weak bonds when heat bonded to each other.
 29. Acatheter shaft as recited in claim 28, wherein said bonding regionincludes bonding between said first tube inside surface and said secondtube outside surface.
 30. A catheter shaft as recited in claim 27,wherein said bonding region includes bonding between said first tubeinside surface and said second tube outside surface.
 31. A cathetershaft as recited in claim 27, wherein said second tube wall is formed ofsubstantially said second material therethrough.
 32. A catheter shaft asrecited in claim 31, wherein said first tube inside surface is formed ofsaid second material proximate said bonding region.
 33. A catheter shaftas recited in claim 32, wherein said first tube has said second materialdisposed over most of said first tube inside surface proximate saidbonding region and distal of said bonding region.
 34. A catheter shaftas recited in claim 33, wherein said first tube includes said secondmaterial as an inside layer, said first material as an outside layer,and a tie-layer disposed between said inside and outside layers.
 35. Acatheter shaft as recited in claim 32, wherein said first tube has saidinside surface formed of said second material proximate said bondingregion and has said inside surface formed of said first material distalof said bonding region.
 36. A catheter shaft as recited in claim 35,further comprising a transition tie-layer disposed between said firstand second materials.
 37. A catheter shaft as recited in claim 36,wherein said second tube includes polyethylene and said first tubeincludes polyethylene proximate said bonding region and said first tubeis formed of PEBA distal of said tie-layer.
 38. A catheter shaft asrecited in claim 27, wherein said first tube inside surface includessaid first material.
 39. A catheter shaft as recited in claim 38,wherein said first tube inside and outside surfaces are formed of saidfirst material.
 40. A catheter shaft as recited in claim 39, whereinsaid first tube is formed of said first material proximate said bondingregion and distal of said bonding region.
 41. A catheter shaft asrecited in claim 40, wherein said second tube has a proximal portionproximate said bonding region having an outside surface formed of saidfirst material.
 42. A catheter shaft as recited in claim 40, whereinsaid second tube is formed of said first material in said proximalportion and formed of said second material distal of said proximalportion and has a transition tie-layer therebetween.
 43. A cathetershaft as recited in claim 40, wherein said second tube is formed of saidsecond material, said second tube proximal portion includes a tie-layerdisposed over said second material and an outer layer of said firstmaterial disposed over said tie-layer.
 44. A catheter shaft as recitedin claim 40, wherein said second tube has said inside layer formed ofsaid second material, a tie-layer disposed over said inside layer, andan outside layer formed of said first material disposed over saidtie-layer.
 45. A catheter shaft as recited in claim 40, wherein saidsecond tube proximal portion is formed of said first material and saidsecond tube distal of said proximal portion is bonded to said proximalportion and has an inside layer formed of said second material, atie-layer disposed over said inside layer, and an outer layer formed ofsaid second material disposed over said tie-layer.
 46. A catheter shaftas recited in claim 40, wherein said second tube proximal and distalportions have an inside layer formed of said second material and anoutside tie-layer disposed over said inside layer.
 47. A catheter shaftcomprising: a first tube including a lumen, an inside wall surface, andan outside wall surface; a second tube having at least a portiondisposed outside of said first tube, said second tube having a length, alumen therethrough, an inside wall surface and an outside wall surface;and a bonding region bonding said second tube outside wall surface tosaid first tube outside wall surface, said second tube outside wallsurface being formed of a second material for a majority of said secondtube length, said first tube wall having a layer of a first materialextending for a majority of said first tube length, said first materialbeing different from said second.
 48. A catheter shaft as recited inclaim 47, wherein said first material includes PEBA and said secondmaterial includes polyethylene.